Center-driven over-limit rotating speed ball mill

Abstract

The utility model provides a center transmission ball mill with over-limit rotation speed, which is not limited by the limit rotation speed, has a simple transmission structure and is convenient to install and maintain, and relates to the technical field of industrial powder preparation. The utility model relates to a center transmission over-limit rotating speed ball mill, which comprises a rack, a barrel and a barrel driving mechanism, the barrel is rotatably arranged on the rack, one end of the barrel is fixedly provided with a feeding hollow shaft coaxial with the barrel, and the other end of the barrel is provided with a transmission shaft coaxial with the barrel; the ball mill further comprises an impact driving mechanism and at least one impact mechanism which is installed in the barrel and arranged around the axis of the barrel, the impact mechanism comprises a planet shaft, and the planet shaft is provided with an impact plate used for scraping, impacting and colliding wall-attached materials in the barrel. The barrel driving mechanism is in transmission connection with one end of the transmission shaft so as to drive the barrel to rotate through the transmission shaft. The efficiency of the ball mill is improved, the transmission structure is simple, and installation and maintenance are convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial powder preparation, in particular to an ultra-limit speed ball mill with central drive. Background Technique

[0002] A ball mill is a basic mechanical grinding equipment, which is widely used in industries such as metallurgy, building materials, and chemical industry, especially in the grinding production of metallurgical ore dressing and building materials cement. The main reasons for the wide application of ball mills are as follows: First, excellent grinding performance, with the powder particles being nearly spherical and the particle size distribution being reasonable; second, stable and reliable continuous operation; third, large single-machine production capacity.

[0003] Since when the rotational speed of the cylinder reaches or exceeds the limit (critical) speed, the grinding media and materials will remain relatively stationary with the cylinder and rotate together with the cylinder, resulting in a "wall-attached" motion state, which causes the materials and grinding media in the ball mill to not collide and impact with each other. Therefore, the rotational speed of the rotating cylinder of the traditional ball mill is lower than the limit (critical) speed (the rotational speed of the rotating cylinder is generally designed according to 70-80% of the critical speed). Limited by the limit speed, in order to ensure the single-machine industrial production capacity scale, a low-speed and high-torque transmission device is the standard configuration and typical feature of the traditional ball mill. Therefore, how to solve the wall-attached problem of the ball mill breaking through the limit speed limit and make the ball mill not limited by the limit speed is the key to improving the production efficiency of the ball mill.

[0004] In addition, in order to meet the requirements of the low rotational speed and high torque of the cylinder of the traditional ball mill, most of the traditional ball mills currently used in industry adopt edge drive with an open gear pair, including a driven gear, a driving gear, and a driving motor. The diameter of the driving gear is smaller than that of the driven gear. The driven gear is sleeved and fixed on the cylinder. The driving gear meshes with the driven gear. The driving motor transmits power to the driving gear through a speed reduction mechanism. The driving motor drives the driving gear to rotate through the speed reduction mechanism, and the driving gear rotates to drive the driven gear to rotate, thereby driving the cylinder to rotate. This transmission method is not convenient for the installation of the driven gear and has problems such as difficult installation and maintenance. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide an ultra-limit speed ball mill with central drive that is not limited by the limit speed, has a simple transmission structure, and is convenient for installation and maintenance.

[0006] The technical solution adopted by the utility model to solve its technical problems is: an ultra-limit speed ball mill with central drive, including a frame, a cylinder, and a cylinder drive mechanism. The cylinder is rotatably installed on the frame. One end of the cylinder is fixedly provided with a feed hollow shaft coaxial with it, and the other end is provided with a transmission shaft coaxial with it. A discharge port is provided on the side of the cylinder at the end where the transmission shaft is provided. A sieve plate for screening materials is installed in the discharge port.

[0007] The ball mill further includes an impact driving mechanism and at least one impact mechanism installed inside the cylinder body and arranged around the axis of the cylinder body so as to revolve around the axis of the cylinder body along with the cylinder body.

[0008] The impact mechanism includes a planetary shaft which is arranged along the axis direction of the cylinder body. The planetary shaft is rotationally connected to the cylinder body so as to be able to rotate around its own axis. An impact plate for scraping, impacting and colliding with the wall-attached materials inside the cylinder body is provided on the planetary shaft.

[0009] The impact driving mechanism is in transmission connection with the planetary shaft to drive the planetary shaft to rotate around its own axis.

[0010] The cylinder driving mechanism is in transmission connection with one end of the transmission shaft to drive the cylinder body to rotate through the transmission shaft.

[0011] Further, the impact driving mechanism includes a fixed gear which is arranged at one end of the cylinder body and coaxially arranged with the cylinder body. The fixed gear is fixedly installed on the frame. One end of the planetary shaft close to the fixed gear extends out of the cylinder body and is provided with a planetary gear which meshes with the fixed gear to drive the planetary shaft to rotate around its own axis.

[0012] Further, the fixed gear is an internal gear, and the planetary gear is arranged inside the fixed gear and meshes internally with the fixed gear.

[0013] Further, the fixed gear is an external gear, and the planetary gear is arranged outside the fixed gear and meshes externally with the fixed gear.

[0014] Further, the cylinder body is rotationally connected to the frame through a feed hollow shaft and a transmission shaft.

[0015] Further, the distance from the planetary shaft to the side wall of the cylinder body is less than the distance from the planetary shaft to the axis of the cylinder body.

[0016] Further, there are at least two impact mechanisms, and the impact mechanisms are evenly arranged around the axis of the cylinder body.

[0017] Further, along the axis direction of the planetary shaft, at least two groups of the impact plates are arranged on the planetary shaft. Each group of the impact plates includes at least two impact plates, and the impact plates of each group are evenly arranged around the planetary shaft.

[0018] Further, along the axis direction of the planetary shaft, the impact plates of adjacent two groups are arranged in a staggered manner.

[0019] Further, a feed guide cylinder which is rotationally matched with the feed hollow shaft is arranged inside the feed hollow shaft.

[0020] The outer end of the feed guide cylinder extends out of the feed hollow shaft and is fixedly connected to the frame; a feed central shaft coaxial with and rotatable in the feed guide cylinder is arranged in the feed guide cylinder, the feed central shaft is fixedly connected to the cylinder body, and a feed pushing structure for pushing the material in the feed guide cylinder into the cylinder body in cooperation with the inner wall of the feed guide cylinder is arranged on the feed central shaft.

[0021] The beneficial effects of the present utility model are as follows: For the center-driven ultra-limit speed ball mill of the present utility model, an impact mechanism is arranged in the cylinder body. The impact mechanism is arranged around the axis of the cylinder body and includes a planetary shaft arranged along the axis direction of the cylinder body and rotatably connected to the cylinder body. During the self-rotation process of the planetary shaft, the impact plate is driven to rotate. During the rotation process of the impact plate, the attached wall materials and grinding bodies in the trajectory area of the impact plate are scraped and impacted, and the attached wall materials and grinding bodies in the nearby area are also impacted and removed, thereby eliminating the attached wall materials, enabling the materials and grinding bodies to effectively impact in the cylinder body, realizing powder grinding at a speed exceeding the limit speed, and improving the efficiency of the ball mill.

[0022] The cylinder driving mechanism of the present utility model drives the cylinder body to rotate through a transmission shaft coaxially arranged at one end of the cylinder body, and the transmission structure is simple, and the installation and maintenance are convenient. Description of the Drawings

[0023] Figure 1 is a structural schematic diagram of a ball mill of the present utility model;

[0024] Figure 2 is another structural schematic diagram of a ball mill of the present utility model;

[0025] Figure 3 is Figure 1 a sectional view taken along A-A;

[0026] Figure 4 is a working schematic diagram when the self-rotation direction of the planetary shaft is the same as the rotation direction of the cylinder body;

[0027] Figure 5 is a working schematic diagram when the self-rotation direction of the planetary shaft is opposite to the rotation direction of the cylinder body;

[0028] Figure 6 is a structural schematic diagram of the impact plates arranged in a staggered manner along the axis direction of the planetary shaft;

[0029] Figure 7 is a structural schematic diagram of the impact plates arranged corresponding to each other along the axis direction of the planetary shaft;

[0030] Figure 8 is a structural schematic diagram of the arrangement of the feed central shaft;

[0031] Figure 9 is a structural schematic diagram of a feed pushing structure;

[0032] As shown in the figure: 1-frame, 2-cylinder, 3-impact mechanism, 4-fixed gear, 5-planetary gear, 6-spherical roller bearing, 8-cylinder drive mechanism, 11-box, 21-feed hollow shaft, 22-discharge port, 23-axis line, 24-screen plate, 25-transmission shaft, 31-planetary shaft, 32-impact drive device, 33-impact plate, area B - the movement trajectory of the impact plate to clean the wall attachment area of ​​the material grinding body, area C - the remaining wall attachment area of ​​the material grinding body, 71-feed center axis, 72-feed spiral belt, 73-support, 74-arc plate. DETAILED DESCRIPTION

[0033] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0034] like Figure 1 As shown, a centrally driven ultra-limited speed ball mill of the utility model comprises a frame 1, a barrel 2 and a barrel driving mechanism 8, wherein the barrel 2 is rotatably mounted on the frame 1 so that the barrel 2 can rotate around its own axis 23, a feeding hollow shaft 21 coaxial with the barrel 2 is fixedly arranged at one end thereof, and a transmission shaft 25 coaxial with the barrel 2 is arranged at the other end thereof, a discharge port 22 is arranged on the side of one end of the barrel 2 provided with the transmission shaft 25, and a sieve plate 24 for screening materials is installed in the discharge port 22; the ball mill also comprises an impact driving mechanism and a sieve plate 24 installed in the barrel 2 and arranged around the axis of the barrel 2 so as to be able to At least one impact mechanism 3 revolves with the cylinder 2 around the axis of the cylinder 2; the impact mechanism 3 includes a planetary shaft 31, the planetary shaft 31 is arranged along the axis direction of the cylinder 2, the planetary shaft 31 is rotatably connected with the cylinder 2 so as to be able to rotate around its own axis, and the planetary shaft 31 is provided with an impact plate 33 for scraping and impacting the wall material in the cylinder 2; the impact drive mechanism is transmission-connected with the planetary shaft 31 to drive the planetary shaft 31 to rotate around its own axis; the cylinder drive mechanism 8 is transmission-connected with one end of the transmission shaft 25 to drive the cylinder 2 to rotate through the transmission shaft 25.

[0035] The feeding hollow shaft 21 and the transmission shaft 25 can be fixed on the cylinder body by bolt connection, welding, etc. Of course, the feeding hollow shaft 21 and the cylinder body can also be an integral structure, and the transmission shaft and the cylinder body can also be an integral structure.

[0036] The screen plate 24 screens the material, specifically blocking the material with a particle size greater than the required size in the cylinder 2 to prevent it from flowing out through the discharge port 22. The screen plate 24 can be installed and fixed in the discharge port 22 by means of clamping, bolting, etc.

[0037] The impact drive mechanism can be a motor, a hydraulic motor, etc. mounted on the cylinder. The cylinder drive mechanism 8 generally adopts a motor.

[0038] When the ball mill of the present utility model is working, the cylinder driving mechanism 8 drives the cylinder 2 to rotate. During the rotation of the cylinder 2, the planetary shaft 31 is driven to rotate around the axis of the cylinder 2, that is, to revolve. The impact driving mechanism drives the planetary shaft 31 to rotate around its own axis. As Figure 4 and as Figure 5 shown, the direction in which the impact driving mechanism drives the planetary shaft 31 to rotate self - rotatably can be the same as or opposite to the rotation direction of the cylinder 2. As Figure 4 shown in, the self - rotation direction of the planetary shaft 31 is the same as the rotation direction of the cylinder. In the figure, the cylinder 2 rotates clockwise and the planetary shaft 31 rotates clockwise self - rotatably. As Figure 5 shown in, the self - rotation direction of the planetary shaft 31 is opposite to the rotation direction of the cylinder. In the figure, the cylinder 2 rotates counterclockwise and the planetary shaft 31 rotates clockwise self - rotatably.

[0039] As Figure 4 and Figure 5 shown, the specific working principle of the ball mill of the present utility model is as follows: Area B indicates the movement track of the impact plate 33 to clean the material grinding body adhering to the wall area, and area C indicates the remaining material grinding body adhering to the wall area. Areas B and C together constitute the entire material grinding body adhering to the wall area; during the working process of the ball mill, the driving mechanism drives the planetary shaft 31 to rotate around its own axis. During the self - rotation process of the planetary shaft 31, the impact plate is driven to rotate. The rotating impact plate 33 scrapes and impacts all the material grinding bodies in area B. The scraped part of the material grinding body in area B moves under force and impacts the adjacent material grinding bodies in area C, causing a chain reaction in the adjacent material grinding bodies in area C, eliminating the material grinding bodies adhering to the wall in area C, and thus breaking through the limit speed limitation of the ball mill. The ball mill of the present utility model arranges the impact mechanism around the axis of the cylinder 2, so that the material grinding body can fall through the central area of the cylinder 2, thereby generating sufficient impact motion. Therefore, the ball mill of the present application has higher ball - milling efficiency and better ball - milling effect (better particle size consistency), higher effective energy utilization rate and lower energy consumption. In addition, since the discharge port 22 of the present utility model is arranged on the side of one end of the cylinder 2, under the action of the centrifugal force generated by the rotation of the cylinder, the materials with qualified particle size in the cylinder can pass through the sieve holes of the sieve plate and flow out from the discharge port 22, and discharging can be achieved without a feeding air flow. Therefore, it can be used for wet grinding. Of course, this ball mill is also suitable for the production of conventional powders. In addition, the cylinder driving mechanism 8 of the present utility model drives the cylinder to rotate through a transmission shaft coaxially arranged at one end of the cylinder, and the transmission structure is simple, and installation and maintenance are convenient.

[0040] It should be noted that, compared with the impact driving mechanism driving the planetary shaft 31 to rotate in the direction opposite to the rotation direction of the cylinder body and the impact driving mechanism 32 driving the planetary shaft 31 to rotate in the same direction as the rotation direction of the cylinder body, at the same self-rotation speed of the planetary shaft 31, the former can make the impact plate have a stronger impact effect and better eliminate the wall attachment effect, but has a certain impact on the effect of driving the material in the cylinder body to rotate and lift, while the latter has a relatively poor impact effect but is beneficial to the lifting of the material in the cylinder body.

[0041] In the embodiment of the present utility model, as Figure 1 and Figure 2 shown, the impact driving mechanism includes a fixed gear 4, the fixed gear 4 is arranged at one end of the cylinder body 2 and is coaxially arranged with the cylinder body 2, the fixed gear 4 is fixedly installed on the frame 1, and one end of the planetary shaft 31 close to the fixed gear 4 extends out of the cylinder body 2 and is provided with a planetary gear 5 meshing with the fixed gear 4 to drive the planetary shaft 31 to rotate around its own axis. Since the fixed gear 4 is fixed on the frame 1, during the process of the planetary shaft 31 revolving around the axis of the cylinder body 2, the planetary gear 5 meshing with the fixed gear 4 will revolve and rotate around the fixed gear 4, so as to drive the planetary shaft 31 to rotate around its own axis while the cylinder body rotates. Specifically, as Figure 1 shown, the fixed gear 4 can be an external gear, and the planetary gear 5 is arranged outside the fixed gear 4 and meshes with the fixed gear 4 externally, as Figure 2 shown, the fixed gear 4 can be an internal gear, and the planetary gear 5 is arranged inside the fixed gear 4 and meshes with the fixed gear 4 internally. As Figure 1 shown, when the fixed gear 4 is an external gear and the planetary gear 5 is arranged outside the fixed gear 4 and meshes with the fixed gear 4 externally, the planetary shaft 31 can be driven to rotate in the same direction as the cylinder body around its own axis during the rotation of the cylinder body; as Figure 2 shown, when the fixed gear 4 is an internal gear and the planetary gear 5 is arranged inside the fixed gear 4 and meshes with the fixed gear 4 internally, the planetary shaft 31 can be driven to rotate in the opposite direction to the cylinder body around its own axis during the rotation of the cylinder body.

[0042] The impact driving mechanism adopts the above-mentioned fixed gear transmission structure, and can directly use the cylinder body driving mechanism to drive the planetary shaft to rotate, which is beneficial to controlling the manufacturing cost of the ball mill.

[0043] It can be understood that the number of impact mechanisms 3 affects the effect of removing the adhering materials, especially the effect of removing the adhering materials in area C. Generally speaking, on the premise of not interfering with each other, the more the number of impact mechanisms 3 in the same cylinder, the more beneficial it is to remove the adhering materials. Specifically, the more the number of impact mechanisms 3, the impact mechanisms 3 can not only scrape the adhering materials on the grinding body, but also generate secondary impacts and throwings on the grinding body of the materials falling on it, making the grinding body of the materials in the cylinder 2 undergo multi-directional dynamic impacts in space. Therefore, it is more beneficial to improve the effect and efficiency of the ball mill. Generally speaking, in order to ensure the balance of the cylinder 2, the impact mechanism 3 is at least two, and the impact mechanisms 3 are evenly arranged around the axis of the cylinder 2, that is, the impact mechanisms 3 are evenly arranged on a circular ring centered on the axis of the cylinder 2. Figure 2 In [the figure], there are eight impact mechanisms 3 and they are evenly arranged around the axis of the cylinder 2.

[0044] It can be understood that the rotational speed of the planetary shaft 31 also affects the effect of removing the adhering materials. Specifically, a suitable value can be obtained through on-site experiments according to the type of materials, the rotational speed of the cylinder 2, the number of planetary shafts, etc. Then, the corresponding fixed gear 4 and planetary gear 5 are selected according to this value.

[0045] In order to protect the fixed gear 4 and the planetary gear 5, in the present utility model, a box body 11 including the fixed gear 4 and the planetary gear 5 is provided on the frame 1.

[0046] As Figure 1 shown, in the present utility model, the cylinder 2 is rotationally connected to the frame 1 through the feed hollow shaft 21 and the transmission shaft 25. The transmission shaft 25 and the feed hollow shaft 21 can be specifically arranged on the cylinder by means of bolt connection, welding or an integral structure with the cylinder. In some embodiments, the cylinder 2 rotates with the frame 1 through the middle part (body part) between the feed hollow shaft 21 and the transmission shaft 25.

[0047] The feed hollow shaft 21 and the transmission shaft 25 can be rotationally connected to the frame 1 through various bearings or shaft linings. In the present utility model, preferably, both the feed hollow shaft 21 and the transmission shaft 25 are rotationally connected to the frame 1 through spherical roller bearings 6 or spherical plain bearings to achieve automatic centering of the cylinder, simplify the manufacturing and installation accuracy of the ball mill, and improve the service life of the ball mill. The planetary shaft 31 can also be rotationally connected to the frame 1 through various bearings or shaft linings. In the present utility model, preferably, the planetary shaft 31 is rotationally connected to the cylinder 2 through a spherical roller bearing 6 to achieve automatic centering of the planetary shaft and simplify the manufacturing and installation accuracy of the planetary shaft.

[0048] The position of the planetary shaft 31 can be set at any position in the area between the side wall of the cylinder 2 and the axis of the cylinder 2. As Figure 3As shown, in the present utility model, optimally, the distance f from the planetary shaft 31 to the side wall of the cylinder 2 is less than the distance e from the planetary shaft 31 to the axis of the cylinder 2. The above structure will inevitably cause the impact plate 33 not to sweep through the central area of the cylinder 2 during the rotation of the planetary shaft 31. In this way, the central area of the cylinder 2 has a relatively large cavity area, which is more conducive to the impact movement of the material grinding body, and can further improve the grinding efficiency and effect of the ball mill.

[0049] The impact plate 33 can be a straight plate, arranged in a spiral structure, etc. Along the axial direction of the planetary shaft 31, only one relatively long impact plate 33 can be arranged. Along the circumferential direction of the planetary shaft 31, one or more impact plates 33 can be arranged. In the present utility model, as Figure 6 、 Figure 7 shown, along the axial direction of the planetary shaft 31, at least two groups of the impact plates 33 are arranged on the planetary shaft 31. Each group of the impact plates 33 includes at least two impact plates 33, and the impact plates 33 of each group are evenly arranged around the planetary shaft 31. Figure 6 In, each group of the impact plates 33 is composed of four impact plates 33. In the present utility model, as Figure 6 、 Figure 7 shown, along the axial direction of the planetary shaft 31, the impact plates 33 of adjacent two groups can be arranged in a staggered manner or in a corresponding manner. In the present utility model, as Figure 6 shown, preferably, along the axial direction of the planetary shaft 31, the impact plates 33 of adjacent two groups are arranged in a staggered manner. The above structure has the best effect on scraping the impact wall-attached material grinding body, can further improve the effect and efficiency of the ball mill, and reduce the energy consumption of the ball mill.

[0050] When the ball mill breaks through the critical speed, with the increase of the cylinder speed, especially when the feed hollow shaft of the cylinder exceeds the critical speed, during the process of the material passing through the feed hollow shaft, it will also be affected by the rotation of the cylinder and cause the problem of wall attachment, resulting in difficult feeding during the operation of the ball mill, easy blockage of materials, and affecting the continuous production stability of the ball mill. Therefore, as Figure 8As shown in the figure, a feed guide cylinder 7 rotatably engaged with the feed hollow shaft 21 is provided inside the feed hollow shaft 21; the outer end of the feed guide cylinder 7 extends out of the feed hollow shaft 21 and is fixedly connected to the frame 1; a feed central shaft 71 coaxial with and rotatable inside the feed guide cylinder 7 is provided inside the feed guide cylinder 7, the feed central shaft 71 is fixedly connected to the cylinder body 2, and a feed pushing structure for pushing the material inside the feed guide cylinder 7 into the cylinder body 2 by cooperating with the inner wall of the feed guide cylinder 7 is provided on the feed central shaft 71. In this way, during the working rotation of the cylinder body, the feed guide cylinder will not be driven to rotate, but the feed pushing structure will be driven to rotate. Therefore, there will be no problem of feed adhering to the wall, and the problem of feed adhering to the wall is transformed into a simple problem of feed accumulation, which is convenient for pushing the material in the feed guide cylinder into the drum; and during the rotation of the feed pushing structure, the wall-adhering material in the feed guide cylinder 7 can be pushed into the cylinder body. Therefore, the above structure solves the problem of the material adhering to the wall when entering the ball mill after the mill exceeds the limit speed, especially when exceeding the limit speed of the feed hollow shaft, which can ensure the continuous production of the ball mill with an ultra-limit speed, improve the production efficiency of the ball mill, and make the feeding and discharging of the ball mill more convenient. The feed pushing structure is not easily worn or damaged.

[0051] Specifically, as Figure 8 shown, in the present utility model, the feed pushing structure includes at least one feed spiral belt 72 wound around the feed central shaft 71. A gap is provided between the feed spiral belt 72 and the feed central shaft 71 to allow air flow and material to enter the cylinder body. The feed spiral belt 72 is fixed to the feed central shaft 71 through a first support 73. Since the feed spiral belt 72 is driven by the cylinder body through the feed central shaft 71 to push the material in the feed guide cylinder 7 into the cylinder body 2, therefore, the specific spiral direction of the feed spiral belt 72 should be set accordingly according to the rotation direction of the cylinder body during operation. Specifically, when the cylinder body rotates clockwise during operation, the feed spiral belt is left-handed; when the cylinder body rotates counterclockwise during operation, the feed spiral belt is right-handed. As Figure 9 shown, in some embodiments, the feed pushing structure also adopts a structure in which multiple arc-shaped plates 74 are provided on the feed central shaft 71, and the arc-shaped plates 74 are inclined with respect to the axis of the feed central shaft 71. The inclination direction of the arc-shaped plates 74 is also set according to the rotation direction of the cylinder body during operation, and the specific principle is the same as the above principle and will not be elaborated specifically. Since the discharge port of the cylinder body is provided on the side of the other end of the cylinder body, centrifugal force can be used for discharging. Thus, during the working process of the ball mill, it is not necessary to introduce air flow from the feed guide cylinder. Therefore, in some embodiments, a solid spiral structure can also be adopted, that is, no gap is provided between the feed spiral belt and the feed central shaft 71.

Claims

1. A center-driven ultra-limiting speed ball mill, comprising a frame (1), a cylinder (2) and a cylinder driving mechanism (8), wherein the cylinder (2) is rotatably mounted on the frame (1), and characterized in that: A coaxial feeding hollow shaft (21) is fixedly disposed at one end of the cylinder (2), and a coaxial transmission shaft (25) is disposed at the other end. A discharge port (22) is disposed on the side of one end of the cylinder (2) where the transmission shaft (25) is disposed. A sieve plate (24) for screening materials is installed in the discharge port (22); The ball mill further comprises an impact driving mechanism and at least one impact mechanism (3) installed in the cylinder (2) and arranged around the axis of the cylinder (2) so as to be able to orbit around the axis of the cylinder (2) along with the cylinder (2); The impact mechanism (3) comprises a planetary shaft (31), the planetary shaft (31) is arranged along the axis direction of the cylinder (2), the planetary shaft (31) is rotatably connected to the cylinder (2) so as to be able to rotate around its own axis, and an impact plate (33) is provided on the planetary shaft (31) for scraping and impacting the wall material in the cylinder (2); The impact drive mechanism is in transmission connection with the planetary shaft (31) to drive the planetary shaft (31) to rotate around its own axis; The cylinder driving mechanism (8) is in driving connection with one end of the transmission shaft (25) so as to drive the cylinder (2) to rotate via the transmission shaft (25).

2. A centrally driven ultra-limiting speed ball mill as claimed in claim 1, characterized in that: The impact drive mechanism comprises a fixed gear (4), the fixed gear (4) being arranged at one end of a cylinder (2) and being coaxially arranged with the cylinder (2), the fixed gear (4) being mounted and fixed on the frame (1), and the planetary shaft (31) extending out of the cylinder (2) at one end close to the fixed gear (4) and being provided with a planetary gear (5) meshing with the fixed gear (4) to drive the planetary shaft (31) to rotate around its own axis.

3. A centrally driven ultra-limiting speed ball mill as claimed in claim 2, characterized in that: The fixed gear (4) is an internal gear, and the planetary gear (5) is arranged inside the fixed gear (4) and meshes with the fixed gear (4).

4. A centrally driven ultra-limiting speed ball mill as claimed in claim 2, characterized in that: The fixed gear (4) is an external gear, and the planetary gear (5) is arranged outside the fixed gear (4) and meshes with the outside of the fixed gear (4).

5. The centrally driven ultra-limiting speed ball mill according to claim 1, characterized in that: The barrel (2) is rotatably connected to the frame (1) via a feeding hollow shaft (21) and a transmission shaft (25).

6. A centrally driven ultra-limiting speed ball mill as claimed in claim 1, characterized in that: The distance between the planetary shaft (31) and the side wall of the cylinder (2) is smaller than the distance between the planetary shaft (31) and the axis of the cylinder (2).

7. The centrally driven ultra-limiting speed ball mill according to claim 1, characterized in that: There are at least two impact mechanisms (3), and the impact mechanisms (3) are evenly arranged around the axis of the cylinder (2).

8. A centrally driven ultra-limiting speed ball mill according to any one of claims 1 to 7, characterized in that: At least two groups of impact plates (33) are arranged on the planetary shaft (31) along the axial direction of the planetary shaft (31), each group of impact plates (33) comprises at least two impact plates (33), and each group of impact plates (33) is evenly arranged around the planetary shaft (31).

9. A centrally driven ultra-limiting speed ball mill as claimed in claim 8, characterized in that: Along the axial direction of the planetary shaft (31), the impact plates (33) of two adjacent groups are arranged in a staggered manner.

10. The centrally driven ultra-limiting speed ball mill according to claim 1, characterized in that: A feed guide cylinder (7) is arranged in the feed hollow shaft (21) and is rotatably matched with the feed hollow shaft (21); The outer end of the feed guide tube (7) extends out from the feed hollow shaft (21) and is fixedly connected to the frame (1); a feed center shaft (71) coaxial with and rotatable therewith is provided inside the feed guide tube (7), the feed center shaft (71) is fixedly connected to the cylinder (2), and a feed pushing structure is provided on the feed center shaft (71) which cooperates with the inner wall of the feed guide tube (7) to push the material in the feed guide tube (7) into the cylinder (2).

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